反应详情

To a solution of methyl (1S,2R)-2-methoxy-4-oxocyclohexanecarboxylate (racemic, cis-isomer from last step) (1.35 g, 7.25 mmol) in methanol (30 mL) was added sodium tetrahydroborate (270 mg, 7.2 mmol) at −78° C. After stirring for 1 h, the reaction was diluted with sat. NH4Cl solution and ethyl acetate. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over Na2SO4, concentrated and purified with flash chromatography (eluting with 70% ethyl acetate in hexanes) to give the desired product (1.26 g, 92%). 1H NMR (500 MHz, CDCl3) δ 3.96 (2H, m), 3.72 (3H, s), 3.38 (3H, s), 2.45 (1H, m), 2.31 (1H, m), 2.11 (1H, m), 1.97 (1H, m), 1.77 (1H, m), 1.50 (2H, m) ppm.

1. extractionThe aqueous layer was extracted with ethyl acetate
2. washThe combined organic layers were washed with brine
3. dry with materialdried over Na2SO4
4. concentrationconcentrated
5. custompurified with flash chromatography (eluting with 70% ethyl acetate in hexanes)